1. Field of the Invention
The instant invention relates to methods of and apparatus for the manufacture of multifilament yarns having interlaced filaments. More particularly, the instant invention relates to methods and apparatus for the manufacture of multifilament yarns having interlaced filaments wherein the filaments are interlaced by impinging at least one stream of fluid on the yarn.
2. Technical Consideration and Prior Art
The filaments of multifilament yarns are cohered together by processes such as twisting, sizing or interlacing. The present invention is directed to interlacing wherein a yarn formed of continuous multifilaments is interlaced or tangled in a generally random way to form "pseudo burls" which cooperate to form a yarn that has a total twist which may be substantially zero.
The prior art suggests several processes for the manufacture of interlaced yarn. These processes include subjecting the yarn, while under slight tension, to the action of at least one fluid jet which is generally created by compressed air. Generally the jet is directed in a plane that is substantially normal to the direction in which the yarn advances and is impinged on the yarn as the yarn traverses what is generally known as an "interlacing nozzle" or "interlace nozzle."
The patent literature, especially the French patent literature, contains many examples of interlacing methods and apparatus for utilization in interlacing the fibers of multifiber yarn. In Addition No. 68,429 to French Pat. No. 1,108,890 a strand of multifiber yarn is advanced between a delivery tube which impinges fluid against the strand and a resonance box. An improvement to this invention is disclosed in French Pat. No. 1,334,130 in which the impinging fluid is recycled from the outlet of the resonance box and again impinged on the yarn.
French Pat. No. 1,492,945 discloses a process in which a multifilament strand of yarn is subjected simultaneously to impingement from pairs of primary fluid jets and at least one secondary jet which impinges fluid on the yarn from a direction opposite that of the primary jets in a zone between the points of impact of the primary jets.
French Pat. No. 2,094,232 discloses a process in which yarn is passed through a conduit and subjected to impingement from two fluid jets which are substantially aligned with the conduit but are oppositely directed.
The aforedescribed processes impinge substantially rectilinear fluid jets on multifilament yarns to interlace the filaments of the yarns. However, there is another approach in which the multifilament yarn is advanced through a zone or station in which there is vortex turbulence created by impinging fluid jets on the yarn which have an axis of rotation which is substantially parallel to the direction in which the yarn advances. In the processes disclosed in these patents, the fluid is fed directly into a conduit forming the interlacing zone or station and the vortex turbulence is formed in the conduit itself. Consequently, in order for the vortex turbulence to be effective, the conduit must extend a relatively long distance and a plurality of inlets for the fluid jets need to be distributed in the conduit along the path therethrough assumed by the yarn.
U.S. Pat. No. 2,191,791 discloses a yarn guide composed of a cavity, the height of which is at most equal to the diameter thereof. As the yarn passes through the cavity, a plurality of radial jets impinge fluid streams upon the yarn and as a result of the action of radial streams, the yarn is interlaced.
French Pat. application No. 72/19404, filed May 25, 1972, now French Pat. No. 2,186,029 in the name of the inventor of the instant invention and entitled "Process and Device for the Manufacture of Interlaced Strand Yarn" is subjected to impingement from jets which generate a perturbed fluid flow. By the term perturbed fluid flow is meant a stream of fluid having a direction and possibly an output which is temporarily variable. With the process disclosed in this application, the interlacing quality of the multifilament yarn is very good because over short lengths there is a random pattern of interlacing without a geometric repetition whereas, over long lengths, the yarn has a pleasing regular appearance. Unfortunately, the apparatus for practicing the process disclosed in this application is rather complicated because it relies on movable mechanical elements to cause perturbation of the fluid jets. Furthermore, this process is relatively noisy and the mechanical elements involved are subject to rapid wear. Finally, it is difficult to obtain similarities in interlacing configurations produced by different nozzles.